Insulation film formation device

ABSTRACT

An SOD system ( 100 A) comprises a process block ( 8 ) for performing a prescribed processing so as to form an insulating film on a wafer W, a carrier block ( 7 ) for transferring the wafer W from the outside into the process block ( 8 ), a sub-transfer mechanism ( 12 ) for transferring the substrate W between the process block ( 8 ) and the carrier block ( 7 ), and a main transfer mechanism ( 15 ). A process tower (T 1 ) prepared by stacking one upon the other a plurality of process units for performing a series of processing for forming an insulating film on the wafer W is arranged detachable from the process block ( 8 ).

TECHNICAL FIELD

The present invention relates to an insulating film-forming apparatusfor forming an insulating film on a substrate such as a semiconductorwafer or an LCD substrate (a glass substrate for a liquid crystaldisplay).

BACKGROUND ART

In the manufacturing process of a semiconductor device, an SOD (Spin onDielectric) method is employed as one of the technologies for forming aninsulating film (an interlayer insulating film) on a semiconductorwafer. In the SOD method, a coating film, i.e., a film formed by thecoating method, is formed on a wafer by a spin coating method, followedby applying a chemical processing or a heat processing or the like tothe coating film so as to form an insulating film. To be more specific,the surface of a wafer is coated first with a chemical liquid preparedby dispersing the material for forming the insulating film in a solvent,followed by evaporating the solvent from the coating film so as to drythe coating film. Then, a baking processing is applied to the driedcoating film so as to cause a chemical reaction to be brought about bythe heating. Finally, the coating film is heated for the curing purpose,thereby obtaining a desired insulating film. Incidentally, depending onthe kind of the chemical liquid used, it is necessary to apply anadditional processing such as the processing under an ammonia gasatmosphere or a chemical processing such as a solvent exchangeprocessing.

An SOD system 400 shown in FIG. 35 and an SOD system 450 shown in FIG.36 are known to the art as the SOD system for carrying out theprocessing described above.

In the SOD system 400 shown in FIG. 35, a carrier 410 housing, forexample, 25 wafers is transferred into a carrier stage 411. The waferswithin the carrier 410 are taken out by a delivery arm 412 and, then,transferred into a process zone 414 through the delivery section of ashelf unit 413 a. A transfer mechanism 415 for transferring the wafer isarranged in the central portion of the process zone 414. Also, aplurality of shelf units, e.g., two shelf units 413 b and 423 c, and aplurality of coating units 416 for coating the wafer with a chemicalliquid are arranged in the vicinity of the transfer mechanism 415. Eachof the shelf units 413 b and 413 c noted above includes a plurality ofprocess units such as heating units for applying a prescribed heatprocessing to the wafer. The transfer mechanism 415 serves to transferthe wafer into and out of these process units. Incidentally, the heatingunit noted above includes, for example, a baking unit for performing abaking processing and a low temperature heating unit for applying adrying processing to the chemical liquid.

It should be noted that various kinds of chemical liquids are used inthe SOD method and, thus, the process conditions of the SOD method arerendered slightly different in many cases depending on the kind of thechemical liquid used. For example, the heat processing under a lowtemperature is required, or it is necessary to carry out the processingunder a different processing atmosphere. Such being the situation, it isnecessary in some cases to change the specifications of the coating unitand the heating unit depending on the kind of the chemical liquid used.Also, even in the case of using the same chemical liquid, it isnecessary in some cases to change the process conditions depending onthe desired thickness of the film that is to be formed. In view of thevariety of the chemical liquids described above, it is not advisable interms of the cost and the footprint to newly prepare a system inaccordance with the change in process.

Under the circumstances, vigorous research is being conducted by thepresent inventors in an attempt to develop an SOD system capable ofcoping with various processes. For example, disclosed in Japanese PatentDisclosure (Kokai) No. 2000-138213 is an SOD system in which a coolingunit, a coating unit, an aging unit, a solvent exchange unit, a curingunit, and a heating unit are arranged in the process section forapplying a series of processing to a substrate.

In the SOD system disclosed in the Japanese patent document quotedabove, the cooling unit, the aging unit, the curing unit, and theheating unit are stacked one upon the other so as to form a process unitgroup of a multi-stage structure. On the other hand, the coating unitand the solvent exchange unit are arranged separately from the processunit group.

However, if a plurality of process units are arranged in a dispersedfashion as in the SOD system quoted above, the footprint of the entireSOD system is increased. Also, the transfer efficiency of the waferwithin the SOD system is rendered poor so as to lower the through-put.Further, a difficulty is generated in the SOD system quoted above inperforming various automatic controls. It should be noted in thisconnection that the wafer is coated with a chemical liquid in thecoating unit and a prescribed heat processing is applied to the coatingfilm in the baking unit, followed by measuring the thickness of thecoating film. If various automatic controls are to be performed on thebasis of the measured data so as to change the process parameters in thecoating unit and the baking unit and to generate an alarm when thethickness of the coating film exceeds a prescribed range, it isdifficult to locate the process unit causing the inconvenience. It isalso difficult to supervise the entire apparatus. Still further, where acertain process unit is in trouble, it is necessary to stop all theprocessing in the SOD system for coping with the process unit that is introuble, with the result that the productivity is lowered.

The SOD system 450 shown in FIG. 36 is described in detail in JapanesePatent Disclosure No. 2003-100621. The SOD system 450 comprises a firstprocess zone 460A. Also, a second process zone 460B and a carrierstation 460C are arranged to have the first process zone 460A sandwichedtherebetween.

The first process zone 460A includes a plurality of coating units 461for coating a wafer with a chemical liquid so as to form a coating film.These coating units 461 are stacked one upon the other so as to form amulti-stage structure. In the coating unit 461, a chemical liquid issupplied from a nozzle onto substantially the center of rotation of awafer held by a spin chuck. In accordance with rotation of the spinchuck, the chemical liquid supplied onto the wafer is spread on thewafer surface so as to form a coating film. The first process zone 460Aalso includes shelf units 462 a and 462 b. Each of these shelf units 462a and 462 b is of a multi-stage structure including, for example, atemperature control unit for controlling the wafer at a prescribedtemperature, a delivery unit, and a low temperature heating unit forheating the wafer having the coating film formed thereon so as to drythe coating film. The process units noted above are stacked one upon theother so as to form each of the shelf units 462 a and 462 b. The waferis transferred into and out of each of these process units by a transfermechanism 463.

The second process zone 460B includes two shelf units 464 a and 464 b ofa heating system. In each of these shelf units 464 a and 464 b, a bakingunit for baking the wafer after the drying processing at a highertemperature and a curing unit for further heating the baked wafer forcuring the coating film are stacked one upon the other so as to form amulti-stage structure. The wafer is transferred into and out of theprocess unit included in each of these shelf units 464 a and 464 b by atransfer mechanism 465.

The carrier station 460C includes a table section 466 on which isdisposed a carrier 470 housing a large number of wafers. The carrierstation 460 also includes a delivery arm 467 for transferring the waferbetween the carrier 470 and the first process zone 460A.

In the SOD system 450, the coating unit 461 and the temperature controlunit are arranged in a process zone differing from that of the bakingunit and the curing unit, as in the SOD system 400 shown in FIG. 35. Inaddition, the coating unit 461 and the temperature control unit arearranged in a dispersed fashion within the same process zone. It followsthat the footprint is also increased in the SOD system 450. Also, sincethe process units are arranged in a dispersed fashion in the SOD system450, the transfer efficiency of the wafer is made poor so as to lowerthe through-put.

Further, in the SOD system 450, the plural coating units 461 are stackedone upon the other within the same shelf unit so as to form amulti-stage structure. As a result, a drain pipe 469 for recovering thewaste chemical liquid discharged from the coating units 461 includes ahorizontal portion as schematically shown in FIG. 37. The waste chemicalliquid discharged from the plural coating units 461 fails to flowsmoothly within the horizontal portion of the drain pipe 469 and tendsto stagnate within the horizontal portion. Since the chemical liquidused in the SOD system tends to be solidified, a serious problem isgenerated that the horizontal portion of the drain pipe 469 is pluggedwith the waste chemical liquid.

It should also be noted that, since the coating units 461 are arrangedside by side and stacked one upon the other, it is necessary to changethe construction of the pipes such as the drain pipe 469 for each of thecoating units 461. What should be noted in this connection is that themanufacturing process of the SOD system is made complex by thedispersion of the specification of the piping so as to give rise to theproblem that the productivity is lowered.

It should also be noted that a chemical liquid tank for storing thechemical liquid is arranged in a region (not shown) different from theregion in which the coating unit 461 is arranged, with the result thatthe supply path of the chemical liquid is prolonged. A cleaningprocessing is applied to the coating unit 461 after completion of theprocessing of a prescribed lot. Since the chemical liquid is notdischarged from the nozzle during the cleaning processing of the coatingunit 461, the cleaning processing is carried out under the state thatthe chemical liquid is left to remain within the supply path. When theprocessing of the succeeding lot is started, a dummy dispensing iscarried out such that all the chemical liquid remaining inside thesupply path is discharged from the supply nozzle. Therefore, it isnecessary to discharge as a waste material a large amount of thechemical liquid remaining inside the supply path, leading to anincreased process cost.

Further, in replacing the chemical liquid tank or in replacing, forexample, the chemical liquid filter connected to the chemical liquidpipe, bubbles of the chemical liquid are generated within the pipe.Naturally, it is necessary to remove the bubbles before the coatingoperation for forming a coating film on the substrate surface. A largeamount of the chemical liquid must be discarded during the operation forremoving the bubbles, if the pipe is long.

DISCLOSURE OF THE INVENTION

A first object of the present invention, which has been achieved in viewof the situation described above, is to provide an insulatingfilm-forming apparatus, which permits diminishing the footprint andwhich also permits improving the transfer efficiency of the substrate.Also, a second object of the present invention is to provide aninsulating film-forming apparatus that permits suppressing the waste of,for example, a chemical liquid.

According to the present invention, there is provided an insulatingfilm-forming apparatus, comprising:

-   -   a substrate process section for applying a prescribed processing        to a substrate for forming an insulating film on the substrate;    -   a substrate transfer section for transferring the substrate from        the outside into the substrate process section; and    -   a substrate transfer mechanism for transferring the substrate        between the substrate process section and the substrate transfer        section;    -   wherein:    -   the substrate process section includes a process tower housed in        a housing and consisting of a plurality of process units, which        are stacked one upon the other, for performing a series of        processing for forming an insulating film on the substrate, said        process tower including a coating unit for coating the substrate        with a chemical liquid containing a material of the insulating        film so as to form a coating film, and a heating unit for        heating the substrate having the coating film formed thereon;        and    -   the process tower is detachable from the substrate process        section.

In the insulating film-forming apparatus of the present inventionpointed out above, it is desirable for the process tower to have a frameof a prescribed shape. It is also desirable for the plural process unitsincluded in the process tower to be detachable from the frame of theprocess tower.

In the insulating film-forming apparatus of the present invention, aplurality of process units required for forming an insulating film arearranged within a single process tower so as to make it possible todecrease the footprint of the insulating film-forming apparatus. Also,the transferring distance of the substrate can be shortened, and thesubstrate can be transferred efficiently so as to achieve a highthrough-put. Further, the construction of the process unit arrangedwithin the process tower can be appropriately changed easily inaccordance with the object, and the process tower itself can be replacedeasily by another process tower in accordance with, for example, thechange in the chemical liquid that is used. As a result, the maintenanceof the process unit arranged within the process tower and themaintenance of the entire process tower can be performed easily.

Also, in the insulating film-forming apparatus of the present invention,it is desirable to connect a unit control device included in each of theplural process units arranged within the process tower for controllingthe processing of the substrate to a tower control apparatus forcontrolling a series of processing performed by the plural process unitsarranged within the process tower. In this case, it is desirable for thetower control apparatus to be constructed to recognize automatically theprocess unit connected to the tower control apparatus. When theinsulating film-forming apparatus is constructed to be capable ofautomatically detecting the change in the construction of the processunit within the process tower, it is possible to apply the processcontrol to the substrate in the entire insulating film-formingapparatus.

Further, it is desirable for the insulating film-forming apparatus ofthe present invention to include at least two substrate process sectionsthat are constructed such that at least one substrate process section isdetachable from the other substrate process section. In other words, itis desirable to construct the insulating film-forming apparatus suchthat an additional substrate process section can be arranged in additionto a single substrate process section that was arranged initially. Inthis case, it is possible to increase the process capacity of theinsulating film-forming apparatus while suppressing the increase in thefootprint of the insulating film-forming apparatus as much as possible.

Further, it is desirable for the coating unit to have a two-stagestructure of a coating process section formed in the upper stage and awaste liquid recovery section formed in the lower stage. In this case,it is desirable to arrange in the coating process section a substrateholding mechanism for holding the substrate substantially flat, achemical liquid supply nozzle for supplying a chemical liquid to thesubstrate held by the substrate holding mechanism, and a cup surroundingthe side surfaces of the substrate held by the substrate holdingmechanism and equipped with a chemical liquid discharge port formed inthe bottom. It is also desirable to arrange in the waste liquid recoverysection a waste liquid tank storing the waste liquid discharged from thedischarge port formed in the cup and a waste liquid passageway section,which does not include a horizontal portion and which serves to guidethe waste liquid discharged from the discharge port formed in the cupinto the waste liquid tank. In this case, the chemical liquid supplypassageway and the waste liquid passageway in the coating unit can bemade optimum so as to prevent the plugging of the waste liquidpassageway. Further, it is desirable to arrange a chemical liquid tankfor storing the chemical liquid used in the coating process section inthe waste liquid recovery section, and to arrange a pump for supplyingthe chemical liquid from the chemical liquid tank into the chemicalliquid supply nozzle in the coating process section. In this case, theliquid supply pipe leading to the chemical liquid supply nozzle can beshortened so as to suppress the waste of the coating liquid.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a horizontal cross sectional view schematically showing theconstruction of an SOD system;

FIG. 2 is an oblique view schematically showing the construction of theSOD system shown in FIG. 1;

FIG. 3 is a side view schematically showing the construction of the SODsystem shown in FIG. 1;

FIG. 4 schematically illustrates the transfer passageway of the waferbetween the carrier and a process tower;

FIG. 5 is an oblique view schematically showing the construction of amain transfer mechanism;

FIG. 6 is a cross sectional view schematically showing the constructionof a coating unit;

FIG. 7 is a cross sectional view schematically showing the constructionof a dummy dispense port;

FIG. 8 is a cross sectional view schematically showing the constructionof a solvent bath;

FIG. 9 is a cross sectional view schematically showing the constructionof a low temperature heating unit;

FIG. 10 is a cross sectional view schematically showing the constructionof a baking unit;

FIG. 11 is a cross sectional view schematically showing the constructionof a measuring unit of a film thickness;

FIG. 12 schematically illustrates how to replace the process units inthe process tower;

FIG. 13 illustrates the arranged state of casings in a housing;

FIG. 14 schematically illustrates the control mode of the SOD systemshown in FIG. 1;

FIG. 15 is a horizontal cross sectional view schematically showing theconstruction of another SOD system;

FIG. 16 schematically illustrates the control mode of the SOD systemshown in FIG. 15;

FIG. 17 is a horizontal cross sectional view schematically showing theconstruction of another SOD system;

FIG. 18 schematically illustrates the construction of the process blockincluded in the SOD system shown in FIG. 15;

FIG. 19 is a horizontal cross sectional view schematically showing theconstruction of another SOD system;

FIG. 20 is a horizontal cross sectional view schematically showing theconstruction of another SOD system;

FIG. 21 is a back view schematically showing the construction of the SODsystem shown in FIG. 20;

FIG. 22 is a cross sectional view schematically showing the constructionof a curing unit;

FIG. 23 is a horizontal cross sectional view schematically showing theconstruction of another SOD system;

FIG. 24 is a back view schematically showing the construction of the SODsystem shown in FIG. 23;

FIG. 25 is a horizontal cross sectional view schematically showing theconstruction of an EB curing unit;

FIG. 26 is a vertical cross sectional view schematically showing theconstruction of the EB curing unit;

FIG. 27 is a plan view showing the construction of an electron beamirradiating apparatus;

FIG. 28 is a horizontal cross sectional view schematically showing theconstruction of another SOD system;

FIG. 29 is a horizontal cross sectional view schematically showing theconstruction of another SOD system;

FIG. 30 is a horizontal cross sectional view schematically showing theconstruction of another SOD system;

FIG. 31 is a horizontal cross sectional view schematically showing theconstruction of another SOD system;

FIG. 32 is a horizontal cross sectional view schematically showing theconstruction of still another SOD system;

FIG. 33 schematically illustrates the construction of another coatingunit;

FIG. 34 schematically illustrates the construction of still anothercoating unit;

FIG. 35 is a plan view schematically showing the construction of aconventional SOD system;

FIG. 36 is a plan view schematically showing the construction of anotherconventional SOD system; and

FIG. 37 schematically illustrates the arrangement of drain pipes forrecovering the waste liquid in the conventional SOD system.

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will now be described withreference to the accompanying drawings.

FIG. 1 is a horizontal cross sectional view schematically showing theconstruction of an SOD system 100A for forming an insulating film by anSOD method, and FIGS. 2 and 3 are an oblique view and a side view,respectively, each showing the construction of the SOD system 100A shownin FIG. 1.

The SOD system 100A comprises a process block 8 for applying aprescribed processing to a wafer W and a carrier block 7 fortransferring the wafer W between a carrier C housing a prescribed numberof wafers W and the process block 8.

The carrier block 7 includes a carrier table 11 on which a plurality ofcarriers, e.g., three carriers C1 to C3, can be disposed and asub-transfer mechanism 12 for transferring the wafer W between thecarriers C1 to C3 disposed on the carrier table 11 and the process block8. The sub-transfer mechanism 12 is arranged within a housing 101.

A plurality of wafers, e.g., 25 wafers W, can be housed in each of thecarriers C1 to C3 such that these wafers W assume a substantiallyhorizontal posture and are positioned a prescribed distance apart fromeach other in the vertical direction (Z-direction) within each of thesecarriers C1 to C3. A wafer transfer port 101 a that can be opened orclosed by a shutter 13 a is formed in the wall of the housing 101 on theside of the carrier table 11.

The sub-transfer mechanism 12 includes a transfer pick 12 a movable inthe X-direction and the Y-direction so as to permit the wafer W to betaken out from within the carriers C1 to C3 for delivery into theprocess block 8 or, by contraries, to permit the wafer W to be taken outfrom within the process block 8 so as to be housed in the carriers C1 toC3. Also, the transfer pick 12 a is rotatable within an XY plane(horizontal plane), movable in the Z-direction, and movable in theY-direction along a guide rail 12 b.

A fan filter unit (FFU) 14 is arranged in an upper portion of thehousing 101 such that a clean air is supplied from the fan filter unit(FFU) 14 into the housing 101 in a manner to form a down flow. As aresult, the attachment of particles to the wafer W is suppressed.

The process block 8 includes a process tower T1 for applying aprescribed processing to the wafer W so as to form an insulating film onthe wafer W, a delivery unit (TRS) 16 for transferring the wafer Wbetween the process tower T1 and the carrier block 7, a UV irradiatingunit (DVT) 17 arranged in the upper stage of the delivery unit (TRS) 16for applying an UV irradiating processing to the surface of the wafer W,and a main transfer mechanism 15 for transferring the wafer W within theprocess block 8. These members of the process block 8 are arrangedwithin a housing 102.

A wafer transfer port 102 a that can be opened or closed by a shutter 13b is formed in that portion of the wall of the housing 102 on the sideof the carrier block 7 which is positioned to face the delivery unit(TRS) 16. Also, a fan filter unit (FFU), not shown, is arranged in anupper portion of the housing 102 so as to supply a clean air into thehousing 102 in a manner to form a down flow.

A plurality of process units for performing a series of processing forforming an insulating film on the wafer W by the SOD method are stackedone upon the other so as to form the process tower T1. In the presentinvention, the series of processing performed in the process tower T1 isdefined to include the processing that handles a chemical liquid and thewaste thereof, and the processing that handles the waste gas containingthe component evaporated from the coating film formed on the wafer W.Therefore, the process tower T1 includes a temperature control unit(CPL) 20 for controlling the wafer at a prescribed temperature beforethe coating step with the chemical liquid containing the material usedfor forming the insulating film, a coating unit (SCT) 18 for coating thewafer surface with the chemical liquid so as to form the coating film, alow temperature heating unit (LHP) 21 for thermally evaporating thesolvent contained in the coating film formed on the wafer surface so asto dry the coating film, and a baking unit (DLB) 22 for heating thewafer W so as to make progress the chemical reaction of the coatingfilm. Further, a film thickness measuring unit 19 for measuring thethickness of the insulating film is also included in the process towerT1, though it is not absolutely necessary for the film thicknessmeasuring unit 19 to be included in the process tower T1.

In the SOD system 100A, a plurality of process units for performing aseries of processing are concentrated in the process tower T1 so as tomake it possible to suppress an increase in the footprint of the processblock 8 as much as possible. As a result, the clean room in which theSOD system is arranged and the fan filter unit (FFU) arranged in theupper portion of the process block 8 can also be miniaturized so as tolessen the burden in the manufacturing cost.

Also, in the process tower T1, the temperature control unit (CPL) 20,the low temperature heating unit (LHP) 21, and the baking unit (DLB) 22are successively stacked one upon the other in the order mentioned onthe upper side of the film thickness measuring unit 19 so as to form aheat processing area in which a prescribed heat processing is applied tothe wafer W. On the other hand, a coating process area comprising thecoating unit (SCT) 18 for forming a coating film on the wafer W isformed on the lower side of the film thickness measuring unit 19. Sincethe process tower T1 is constructed such that the diffusion of heat fromthe heating process area into the coating process area is suppressed bythe film thickness measuring unit 19, it is possible to suppress anonuniformity in quality of the coating film, which is caused by thechange in temperature, in the coating unit (SCT) 18. As a result, acoating film of a stable quality can be formed. Incidentally, the upperside of the baking unit (DLB) 22 is utilized as a space for housing, forexample, a motor or another electric system, or as an exhaust area forhousing, for example, an exhaust pipe.

FIG. 4 schematically illustrates the transfer passageway of the wafer Wbetween the carriers C1 to C3 disposed on the carrier table 11 and theprocess tower T1. In the drawing, the process tower T1 is shown on theleft side of the main transfer mechanism 15 for simplifying thedescription. However, the process tower T1 is actually arranged rearwardof the main transfer mechanism 15 on the paper as shown in FIG. 1.

The delivery unit (TRS) 16 includes a delivery stage 16 a of the wafer Wonto which the wafer can be delivered by each of the sub-transfermechanism 12 and the main transfer mechanism 15. The wafer W transferredout of the carriers C1 to C3 by means of the sub-transfer mechanism 12is disposed on the delivery stage 16 a and, then, further transferred bythe main transfer mechanism 15 from the delivery stage 16 a. Bycontraries, the wafer W subjected to a prescribed processing in theprocess tower T1 is transferred by the main transfer mechanism 15 intothe delivery unit (TRS) 16 and, then, further transferred from thedelivery unit (TRS) 16 by the sub-transfer mechanism 12.

The UV irradiating unit (DVT) 17 is operated in the case where, forexample, the wafer W is coated twice with the chemical liquid. To bemore specific, the UV irradiating unit (DVT) 17 is operated to apply aUV irradiating processing to the wafer surface coated with a first lotof the chemical liquid, i.e., to the coating film of the chemical liquidformed first on the wafer surface, so as to improve the wettability ofthe substrate surface with the chemical liquid and, then, the substratesurface coated with the first of the chemical liquid is further coatedwith a second of the chemical liquid. The UV irradiating unit (DVT) 17comprises a stage on which the wafer W is disposed and an UV lamp forirradiating the wafer W disposed on the stage with an ultraviolet lighthaving a prescribed wavelength, though the detailed construction of theUV irradiating unit (DVT) 17 is not shown in the drawing. Incidentally,it is possible to arrange the UV irradiating unit (DVT) 17 in theprocess tower T1.

The sub-transfer mechanism 12 is incapable of gaining access to any ofthe process tower T1 and the UV irradiating unit (DVT) 17, and the maintransfer mechanism 15 alone is capable of gaining access to theseapparatuses. In the SOD system 100A, the main transfer mechanism 15alone is utilized for transferring the wafer W within the process block8. As a result, the footprint of the process block 8 can be muchsuppressed. Also, since a plurality of process units for performing aseries of processing are arranged in a concentrated fashion in theprocess tower T1, the total transfer distance of the wafer W can beshortened. As a result, the transfer efficiency of the wafer W isenhanced so as to improve the through-put of the transfer, leading to ahigh through-put of the entire SOD system 100A.

FIG. 5 is an oblique view schematically showing the construction of themain transfer mechanism 15. As shown in the drawing, the main transfermechanism 15 includes three arms 61 a to 61 c each holding a singlewafer W, a base 62 movably supporting these arms 61 a to 61 c, a pair ofguide rails 63 a and 63 b supporting the base 62 such that the base 62can moved in the vertical direction, joining members 64 a, 64 b forfixing the upper edges and the lower edges, respectively, of the guiderails 63 a, 63 b, and a rotary driving section 65 mounted to the joiningmember 64 b for rotatably driving around a vertical axis a housingformed of the guide rails 63 a, 63 b and the joining member 64 a, 64 b.It should be noted that the three arms 61 a to 61 c of the main transfermechanism 15 are collectively movable in the vertical direction,collectively swingable about a vertical axis, and independently movableback and forth in the horizontal direction.

Each process unit arranged within the process tower T1 will now bedescribed in detail. FIG. 6 is a cross sectional view schematicallyshowing the construction of the coating unit (SCT) 18. The coating unit(SCT) 18 includes a casing 55 a. The casing 55 a is divided into anupper stage and a lower stage. A coater area 18A in which the wafer W isprocessed is formed in the upper stage. Also, a tank area 18B forsupplying various chemical liquids and a cleaning liquid used in thecoater area 18A and for recovering the waste liquids from the coaterarea 18A is formed in the lower stage. In short, the coating unit (SCT)18 is of a two-stage structure. Incidentally, the drawing shows that thecoater area 18A and the tank area 18B are formed integral within thecasing 55 a. Alternatively, it is also possible to employ a separableconstruction such that the casing forming the coater area 18A and thecasing forming the tank area 18B are separable from each other.

The air controlled at a prescribed temperature and humidity is suppliedfrom a temperature-humidity control section 69 into the coating unit(SCT) 18. The air supplied into the coater area 18A is partly dischargedto the outside of the casing 55 a through an exhaust port 68 formed inthe casing 55 a. By controlling the inner region of the coating unit(SCT) 18 at a prescribed temperature and humidity, the conditions in thestep of forming the coating film can be made constant so as to make itpossible to maintain constant the characteristics of the coating filmthus formed.

Arranged in the coater area 18A are a spin chuck 35 holding the wafer Wsubstantially horizontal by means of vacuum suction, a motor forrotating the spin chuck 35, a driving section 23 including a liftmechanism for moving the spin chuck 35 in the vertical direction, a cup24 arranged to surround the periphery of the spin chuck 35 so as torecover the chemical liquid scattered from the wafer W held by the spinchuck 35, a supply nozzle 25 for supplying the chemical liquid ontosubstantially the center of rotation of the wafer W held by the spinchuck 35, a pump 26 for supplying the chemical liquid into the supplynozzle 25, a dummy dispense port 27 for allowing the supply nozzle 25 toperform the dummy dispense of, for example, the chemical liquidremaining in the supply nozzle 25, a solvent bath 28 for suppressing thedrying at the tip of the supply nozzle 25, and a nozzle-moving mechanism(not shown) for moving the supply nozzle 25 between a prescribedposition above the wafer W and a region including the dummy dispenseport 27 and the solvent bath 28.

On the other hand, arranged in the tank area 18B are a chemical liquidtank 29 for storing the chemical liquid, a waste liquid tank 30 forstoring the waste liquid discharged from the coater area 18A, and awaste liquid recovery vessel 31 for recovering the waste liquiddischarged from the coater area 18A.

For example, if the arm of the main transfer mechanism 15, e.g., the arm61 a holding the wafer W, is inserted into the coater area 18A so as tobe positioned above the spin chuck 35, the spin chuck 35 is moved upwardto receive the wafer W from the arm 61 a. After the arm 61 a isretreated from the coater area 18A and the spin chuck 35 is moveddownward to a prescribed position, a chemical liquid used for forming aninsulating film is supplied from the supply nozzle 25 onto substantiallythe center of the surface of the wafer W held by the spin chuck 35 and,then, the spin chuck 35 is rotated at a prescribed rotating speed. As aresult, the chemical liquid is centrifugally spread in the radialdirection of the wafer W and, thus, a coating film is formed on thesurface of the wafer W.

A drain pipe 24 a extending downward in substantially the verticaldirection is connected to the bottom wall of the cup 24. The lower edgeof the drain pipe 24 a is open and connected to the waste liquidrecovery vessel 31. The chemical liquid scattered from the wafer W inaccordance with rotation of the spin chuck 35 and received by the cup 24is guided through the drain pipe 24 a into the waste liquid recoveryvessel 31.

FIG. 7 is a cross sectional view schematically showing the constructionof the dummy dispense port 27. The dummy dispense port 27 includes aliquid receiving section 27 a for receiving the chemical liquiddischarged from the supply nozzle 25, a discharge pipe 27 b connected atone end to the liquid receiving section 27 a, and a thinner dischargingnozzle 27 c for discharging a liquid thinner used as a solvent of thechemical liquid. In performing the dummy dispense operation, the supplynozzle 25 is held under the state that the tip of the supply nozzle 25is pushed into an upper portion of the liquid receiving section 27 a,and a thinner is discharged from the thinner discharging nozzle 27 ctoward the tip portion of the supply nozzle 25 to remove the chemicalliquid attached to the supply nozzle 25. The other edge of the dischargepipe 27 b connected to the waste liquid recovery vessel 31 is open so asto permit the chemical liquid discharged from the supply nozzle 25 andthe thinner liquid discharged from the thinner discharging nozzle 27 cduring the dummy dispense operation to be introduced into the wasteliquid recovering vessel 31.

FIG. 8 is a cross sectional view schematically showing the constructionof the solvent bath 28. The solvent bath 28 is formed of a hermeticcontainer 28 a including a storing section 28 c for storing the thinnerliquid acting as a solvent of the chemical liquid. A vapor atmosphere ofthe solvent is formed within the hermetic container 28 a. When thechemical liquid is not discharged, the supply nozzle 25 is held underthe state that the tip portion of the supply nozzle 25 is inserted intothe inner region of the hermetic container 28 a. The tip of the supplynozzle 25 can be prevented from being dried because the tip of thesupply nozzle 25 is exposed to the vapor atmosphere of the solvent whenthe chemical liquid is not supplied. Incidentally, a discharge pipe 28 bof, for example, the solvent is connected at one edge to the bottom ofthe hermetic container 28 a. The other edge of the discharge pipe 28 bis open to the waste liquid recovery vessel 31.

The waste liquid recovery vessel 31 formed within the tank area 18Bcovers the open edge of the drain pipe 24 a of the cup 24 and the openedges of the discharge pipes 27 b, 28 b of the dummy dispense port 27and the solvent bath 28, respectively. Also, a pipe 31 a extendingdownward in the vertical direction is connected at the upper edge to thebottom portion of the waste liquid recovery vessel 31. The waste liquidrecovery vessel 31 is formed such that the portion to which the pipe 31a is connected is positioned in the deepest point and that the innersurface of the waste liquid recovery vessel 31 is gradually inclineddownward from the peripheral portion toward the pipe 31 a.

A funnel 32 is mounted to the pipe 31 a in a manner to cover the loweredge portion of the pipe 31 a. The waste liquid discharged from the pipe31 a flows downward along the inner surface of the funnel 32 so as to bedischarged to the outside through an opening formed in the lower edge ofthe funnel 32. The funnel 32 can be moved in the vertical direction by alift mechanism 33. When the waste liquid is to be stored in the wasteliquid tank 30, the funnel 32 is held at a low position such that thelower edge of the funnel 32 is positioned in the vicinity of an inletport 30 a of the waste liquid tank 30. On the other hand, when, forexample, the waste liquid tank 30 is renewed, the funnel 32 is movedupward so as to permit the lower edge of the funnel 32 to be positionedsufficiently apart from the inlet port 30 a.

As described above, the waste liquid passageway for discharging thewaste liquid from the coater area 18A into the waste liquid tank 30 isformed of the drain pipe 24 a, etc., the pipe 31 a and the funnel 32.What should be noted is that the waste liquid passageway noted abovedoes not include a substantially horizontal portion. As a result, thewaste liquid discharged from the coater area 18A is unlikely to stagnatein the waste liquid passageway until the waste liquid is introduced intothe waste liquid tank 30. It follows that the waste liquid is unlikelyto be solidified so as to make it possible to recover smoothly the wasteliquid.

A liquid supply pipe 34 a formed between the chemical liquid tank 29arranged within the tank area 18B and the pump 26 arranged within thecoater area 18A extends over substantially the shortest distance.Likewise, a liquid supply pipe 34 b formed between the pump 26 and thesupply nozzle 25 extends over substantially the shortest distance. As aresult, it is possible to decrease the amount of the chemical liquidthat is discharged when the bubbles are removed during, for example, thedummy dispense operation and during the replacement of the chemicalliquid tank 29.

Incidentally, in the embodiment described above, the coating unit (SCT)18 is constructed such that the chemical liquid dripped onto the centralportion on the surface of the wafer W is centrifugally spread in theradial direction of the wafer W by the rotation of the wafer W so as toform a chemical liquid layer on the surface of the wafer W.Alternatively, it is also possible to employ a so-called “single stroketype coating device”, i.e., a scan coating device in which the nozzlefor supplying the chemical liquid is moved relative to the wafer so asto supply the chemical liquid onto the wafer surface in the form of, forexample, a rectangular wave. It is also possible to employ an apparatususing a slit type nozzle that supplies the chemical liquid in the formof a band.

The heat processing area will now be described. FIG. 9 is a crosssectional view schematically showing the construction of the lowtemperature heating unit (LHP) 21. The low temperature heating unit(LHP) 21 comprises a heating plate 41 and a lid 42 collectively forminga processing container 40, a lift pin 43 for delivering the wafer W ontothe main transfer mechanism 15 and onto the heating plate 41, a liftmechanism 43 a for moving the lift pin 43 in the vertical direction, anda lift mechanism 44 for moving the lid 42 in the vertical direction.

A heater 41 a that generates heat by an electric power supplied from apower supply section 41 b is buried in the heating plate 41. As aresult, the heating plate 41 can be maintained at a prescribedtemperature, e.g., about 100° C. to about 130° C. Also, a proximity pin41 c for supporting the wafer W is formed on the upper surface of theheating plate 41, and the lift pin 43 extends through the heating plate41. A gas supply port 42 a and an exhaust port 42 b for exhausting theinner region of the processing container 40 are formed in the lid 42. Anitrogen gas (N₂) supplied from a nitrogen gas supply source (not shown)is introduced into the processing container 40 through the gas supplyport 42 a formed in the lid 42.

If the arm of the main transfer mechanism 15, e.g., the arm 61 a holdingthe wafer W, is inserted into the clearance between the heating plate 41and the lid 42 included in low temperature heating unit (LHP) 21 underthe state that the lid 42 is moved upward, the lift pin 43 is movedupward so as to receive the wafer W from the arm 61 a. If the lift pin43 is moved downward after the arm 61 a is retreated, the wafer W issupported by the proximity pin 41 c. Then, the lid 42 is moved downwardso as to hermetically close the processing container 40. Under thiscondition, a nitrogen gas is substituted within the processing container40 so as to form a low oxygen atmosphere, followed by heating theheating plate 41 to a prescribed temperature, e.g., 100° C. As a result,the solvent contained in the coating film formed on the wafer W isevaporated so as to dry the coating film.

Incidentally, the temperature control unit (CPL) 20 is substantiallyequal in construction to the low temperature heating unit (LHP) 21,except that a wafer table equipped with a cooling mechanism, i.e., acooling plate, is arranged in the temperature control unit (CPL) 20 inplace of the heating plate 41 equipped with the heater 41 a, though thedetailed construction of the temperature control unit (CPL) 20 is notshown in the drawing. The wafer W is disposed on the cooling plate for aprescribed time in the temperature control unit (CPL) 20 so as tocontrol the wafer W at a prescribed temperature.

FIG. 10 is a cross sectional view schematically showing the constructionof the baking unit (DLB) 22. As shown in the drawing, the baking unit(DLB) 22 comprises a heating plate 46 and a lid 47 collectively forminga processing container 45, a casing 48 surrounding the heating plate 46,a lift pin 49 extending through the heating plate 46 and the bottomplate of the casing 48, a lift mechanism 49 a for moving the lift pin 49in the vertical direction, and a lift mechanism 50 for moving the lid 47in the vertical direction.

A wafer transfer port (not shown) is formed in one side wall of thecasing 48. It is possible for the arms 61 a to 61 c of the main transfermechanism 15 to be moved through the wafer transfer port fortransferring the wafer W. Also, an exhaust port 48 b for exhausting theinner region of the casing 48 is formed in another side wall of thecasing 48. It should be noted that an open portion 48 a formed in theupper wall of the casing 48 is closed by the lid 47.

A heater 46 a that generates heat by an electric power supplied from apower supply section 46 b is buried in the heating plate 46. As aresult, it is possible to maintain the heating plate 46 at a prescribedtemperature, e.g., about 150° C. to about 350° C. Also, a proximity pin46 c for supporting the wafer W is formed on the upper surface of theheating plate 46, and the lift pin 49 extends through the heating plate46 and the bottom plate of the casing 48. Further, a gas supply port 47a and an exhaust port 47 b for exhausting the inner region of theprocessing container 45 are formed in the lid 47. A nitrogen gas (N₂)supplied from a nitrogen gas supply source (not shown) is introducedthrough the gas supply port 47 a into the processing container 45.

The baking unit (DLB) 22 is substantially equal to the low temperatureheating unit (LHP) 21 in the mode of the heat processing. Specifically,the wafer W transferred by the main transfer mechanism 15 through thewafer transfer port (not shown) formed in the casing 48 is received bythe lift pin 49 and, then, disposed on the heating plate 46. Further,the processing container 45 is hermetically closed. Under thiscondition, an N₂ gas atmosphere is set up within the processingcontainer 45, and the heating plate 46 is heated to a prescribedtemperature so as to apply a baking processing to the wafer W.

FIG. 11 is a cross sectional view schematically showing the constructionof the film thickness measuring unit 19. As shown in the drawing, thefilm thickness measuring unit 19 comprises a casing 51 having a transferport 51 a formed in the side wall thereof, a table 52 arranged withinthe casing 51 for allowing the wafer W to be disposed thereon, a drivingmechanism 53 for rotating the table 52 and moving the table 52 in the X-and Y-directions, and a light interference type film thickness meter 54.

The light interference type thickness meter 54 includes a probe 54 apositioned to face the surface of the wafer W disposed on the table 52,an optical fiber 54 b, and a spectroscopic unit 54 c including aspectroscope and a controller. The light interference type filmthickness meter 54 obtains a spectrum on the basis of the reflectedlight of the light irradiating the surface of the wafer W and detectsthe film thickness based on the spectrum thus obtained.

In the film thickness measuring unit 19, the wafer W is moved in the X-and Y-directions, with the result that the probe 54 a is allowed to facethe wafer W in many points along, for example, the diameter of the waferW. It follows that the film thickness is measured by the probe 54 a atmany points of the wafer W.

The process tower T1 housing the various process units described aboveis detachable from the housing 102 as shown in FIG. 2. In other words,it is possible to exchange the process tower T1 for another processtower. In the SOD method, many kinds of chemical liquids are used. Sincethe process step and the process conditions such as the processatmosphere are changed depending on the kind of the chemical liquidused, it is advisable to prepare in advance a plurality of processtowers each consisting of a plurality of process units handling the samekind of the chemical liquid. If the required process tower isincorporated in the process block 8, it is possible to change easily theSOD system 100A to conform with the kind of the chemical liquid usedwithout applying a cleaning processing to the coating unit and withoutchanging the process recipe of each of the heat processing units. Also,since it is possible to finish a series of processing handling a wasteliquid and a waste gas in a single process tower, it is possible toseparate completely the chemicals that must not be mixed because aharmful substance may be generated by the mixing. It follows that thesafety can be enhanced. Further, where some of the process unitsarranged within the process tower T1 have got out of order, it ispossible to substitute another process tower (or an auxiliary processtower) for the process tower T1 so as to make it possible to continuethe processing of the wafer W.

It is possible to substitute other process units for the various processunits arranged within the process tower T1. FIG. 12 schematically showsthe mode of replacement of the process unit in the process tower T1. Asdescribed previously, arranged in the process tower T1 are the filmthickness measuring unit 19, the temperature control unit (CPL) 20, thelow temperature heating unit (LHP) 21, and the baking unit (DLB) 22.These process units 19 to 22 are housed in the casings 55 b to 55 e,respectively, and the casing 55 a constitutes the coating unit (SCT) 18.Wafer transfer ports 56 a to 56 e for transferring the wafer W into andout of the casings 55 a to 55 e are formed in the side walls of thecasings 55 a to 55 e.

In the process tower T1, it is possible to pull, for example, the casing55 d out and the low temperature heating unit (LHP) 21 housed in thecasing 55 d and to arrange a casing 55 d′ accommodating a prescribedprocess unit in the free space formed by pulling the casing 55 d out.The particular construction makes it possible to optimize theconstruction of the process unit arranged within the process tower T1 inaccordance with the processing procedure of the wafer W. Also, wheresome of the process units have got out of order, it is possible toreplace the particular process units alone by other process units (orauxiliary process units) so as to make it possible to avoid the decreaseof the productivity.

FIG. 13 shows how the casings 55 a to 55 e are housed in a housing 57.The casings 55 a to 55 e are detachable from the housing 57 (not shownin FIG. 12). A clearance 58 is formed between the casings 55 a to 55 eand the inner surface of the housing 57. The air discharged from theexhaust port 68 (see FIG. 6) formed in the casing 55 a of the coatingunit (SCT) 18, the temperature and humidity of the discharged air beingcontrolled, flows into the clearance 58. The air flowing through theclearance 58 is discharged to the outside by an exhaust device 59through an exhaust port 57 a formed in the housing 57.

The control mode of the SOD system 100A will now be described. FIG. 14shows the entire SOD system 100A and the control mode thereof. A systemcontrol apparatus AS1 for controlling the entire SOD system 100Acomprises a CPU, a memory, a program stored in the memory, etc. andserves to control directly shutters 13 a, 13 b, the sub-transfermechanism 12, the main transfer mechanism 15, the fan filter unit (FFU)14, etc., which are essential constituents. Also, as described hereinlater, it is possible to connect a prescribed number of control devicesincluding the unit control device for controlling each of the variousprocess units, the tower control apparatus for controlling the processtower, and the block control device for controlling the additionalprocess blocks arranged later to the system control apparatus AS1.

The UV irradiating unit (DVT) 17 is controlled by a unit control device90A. To be more specific, an electric signal indicating, for example,the transfer state of the wafer W is transmitted between the unitcontrol device 90A and the system control apparatus AS1 so as to permitthe wafer W to be transferred smoothly into or out of the UV irradiatingunit (DVT) 17. Each of the UV irradiating unit (DVT) 17 and the unitcontrol device 90A has an inherent ID number. Also, each of the unitcontrol device 90A and the system control apparatus AS1 is equipped witha prescribed hardware and a prescribed software such that, if the unitcontrol device 90A is connected to the system control apparatus AS1, thesystem control apparatus AS1 automatically recognizes the unitinformation such as the control parameter of the UV irradiating unit(DVT) 17 as denoted by ‘AD’ in FIG. 14.

As the method of the automatic recognition described above, it ispossible to employ the method that the ID number and the unitinformation are transmitted from the unit control device 90A to thesystem control apparatus AS1. It is also possible to employ the methodthat the system control apparatus AS1 is provided with the data base inwhich the unit information for each ID number is stored. In this case,if the ID number is transmitted from the unit control device 90A to thesystem control apparatus AS1, the unit information relating to the IDnumber is searched in the system control apparatus AS1 by utilizing thedata base.

A tower control apparatus AT1 formed of a CPU, a memory, a programstored in the memory, etc. serves to control the entire process towerT1, i.e., serves to prepare and supervise the process recipe for each ofthe process units arranged in the process tower T1.

The coating unit (SCT) 18, the film thickness measuring unit 19, thetemperature control unit (CPL) 20, the low temperature heating unit(LHP) 21, and the baking unit (DLB) 22 arranged in the process tower T1are operated by an exclusive unit control devices 90B, 90C, 90D, 90E and90F, respectively. For example, the coating unit (SCT) 18 and the unitcontrol device 90B thereof have an inherent ID number. If the unitcontrol device 90B is connected to the tower control apparatus AT1, theunit information on the coating unit (SCT) 18 is automaticallyrecognized by the tower control apparatus AT1. The particularconstruction is also employed in each of the film thickness measuringunit 19, the temperature control unit (CPL) 20, the low temperatureheating unit (LHP) 21, and the baking unit (DLB) 22.

Incidentally, the unit control device 90B for the coating unit (SCT) 18serves to move the spin chuck 35 in the vertical direction and to rotatethe spin chuck 35, to move the supply nozzle 25, to permit the chemicalliquid to be discharged from the supply nozzle 25, and to operate thepump 26. The unit control device 90C for the film thickness measuringunit 19 serves to permit the driving mechanism 53 to drive the table 52in the X- and Y-directions, to process the signal obtained from thespectroscopic unit 54 c so as to determine the thickness in variouspoints of the wafer W, to prepare a film thickness distribution chart,and to obtain an average thickness of the film. The unit control device90E for the low temperature heating unit (LHP) 21 serves to control theoutput from the power supply section 41 b to the heater 41 a, to controlthe lift mechanisms 43 a and 44, and to control the supply and exhaustof the N₂ gas. Further, the unit control device 90F for the baking unit(DLB) 22 serves to control the output from the power supply section 46 bto the heater 46 a, to control the lift mechanisms 49 a and 50, and tocontrol the supply and exhaust of the N₂ gas.

The unit information on each of the process units arranged in theprocess tower T1 is stored in the tower control apparatus AT1. When thetower control apparatus AT1 is connected to the system control apparatusAS1, the unit information stored in the tower control apparatus AT1 isautomatically recognized by the system control apparatus AS1. As aresult, it is possible for the system control apparatus AS1 to grasp theconstruction of the SOD system 100A. Because of the particular controlmode, the processing process of the wafer W can be supervised easily inthe SOD system 100A.

As described previously, each of the process units arranged within theprocess tower T1 can be replaced easily by another process unit.Therefore, where a process unit arranged in the process tower T1 isreplaced by another process unit, the unit control device accompanyingsaid another process unit is connected to the tower control apparatusAT1. As a result, the tower control apparatus AT1 automaticallyrecognizes the new process unit so as to prepare a process recipe of theprocess tower T1 of the new construction, and the processing of thewafer W in the new process tower T1 is controlled. Where the processtower T1 is constructed to be controlled by the tower control apparatusAT1 as described above, the process unit arranged within the processtower T1 can be replaced easily.

Also, the process tower T1 is detachable from the housing 102 asdescribed previously. Therefore, where the process tower T1 is replacedby another process tower, the tower control apparatus AT1 is alsoreplaced simultaneously by another tower control apparatus for saidanother process tower, and said another tower control apparatus isconnected to the system control apparatus AS1. As a result, the systemcontrol apparatus AS1 automatically recognizes said another processtower and the construction of the process units arranged in the newprocess tower so as to control the SOD system of the new construction.

Incidentally, it is possible to allow the tower control apparatus AT1 toperform the function of correcting the process parameter of each of theprocess units arranged in the process tower T1 based on the data on thefilm thickness measured in the film thickness measuring unit 19. Thedata on the film thickness measured in the film thickness measuring unit19 are transferred into the tower control apparatus AT1, and the towercontrol apparatus AT1 serves to correct the corresponding processparameter based on the measured data. Then, the parameter after thecorrection is transferred into the relating unit control device.

In the case of measuring, for example, the thickness of the coating filmformed in the coating unit (SCT) 18, the parameter corrected in thetower control apparatus AT1 includes, for example, the rotating speedand the rotating time of the spin chuck 35, the temperature and humiditywithin the coating unit (SCT) 18, the temperature of the chemicalliquid, and the discharging rate of the chemical liquid. On the otherhand, in the case of measuring the thickness of the insulating filmformed by the processing in the baking unit (DLB) 22, the parametercorrected in the tower control apparatus AT1 includes, for example, theheating time and the heating temperature, the N₂ concentration, and theoxygen concentration in the baking unit (DLB) 22.

It is desirable to generate an alarm in the case where the filmthickness measuring unit 19 has measured an abnormal film thickness thatcannot be coped with by the correction of the parameter in each of theprocess units arranged in the process tower T1, said correction beingperformed by the tower control apparatus AT1. In this case, it ispossible to continue the processing of the wafer W in the SOD system100A by removing the process tower T1 from the SOD system 100A and bymounting another process tower in the SOD system 100A in place of theprocess tower T1. It is possible to examine in detail the cause of thetrouble and to repair and improve the defective point in respect of theprocess tower T1 removed from the SOD system 100A.

The process step of the wafer W within the SOD system 100A will now bedescribed. In the first step, the carriers C1 to C3 each housing, forexample, 25 wafers are transferred from the outside onto the carriertable 11 included in the carrier block 7 by an automatic transfer robotor by the manual operation by the operator. Then, the sub-transfermechanism 12 takes out the wafer W from the carrier C1 and transfers thewafer W onto the delivery unit (TRS) 16 included in the process block 8.Further, the main transfer mechanism 15 takes out the wafer W from thedelivery unit (TRS) 16 so as to transfer the wafer W into thetemperature control unit (CPL) 20 arranged in the process tower T1. Thewafer W is controlled at a prescribed temperature (e.g., 23° C.) withinthe temperature control unit (CPL) 20. The wafer W having thetemperature controlled is transferred by the main transfer mechanism 15into the coating unit (SCT) 18. Within the coating unit (SCT) 18, thewafer W is coated with a chemical liquid and, thus, a coating film isformed on the wafer W.

After the coating film is formed within the coating unit (SCT) 18 on thefirst wafer W transferred out of the carrier C1, the first wafer W istransferred by the main transfer mechanism 15 into the film thicknessmeasuring unit 19 for measuring the thickness of the coating film. Themeasured data on the thickness of the coating film is transmitted fromthe unit control device 90C for the film thickness measuring unit 19 tothe tower control apparatus AT1. If the data on the thickness of thecoating film falls within a range of the prescribed standard, the towercontrol apparatus AT1 permits a prescribed processing to be successivelycontinued within the process tower T1 without changing the controlparameter of the coating unit (SCT) 18. On the other hand, where thedata on the thickness of the coating film fails to fall within the rangeof the prescribed standard, but falls within an allowable range inrespect of the correction of the thickness, a prescribed parameter inthe coating unit (SCT) 18 (e.g., the rotating speed of the spin chuck35) is corrected by the tower control apparatus AT1, and the correctedvalue is supplied to the unit control device 90B for the coating unit(SCT) 18. After the correction of the process parameter, the processingfor forming the coating film is carried out in the coating unit (SCT) 18in accordance with the corrected process parameter. On the other hand,where the data on the thickness of the coating film fails to fall withinthe range of the prescribed standard and also fails to fall within anallowable range in respect of the correction of the thickness, the towercontrol apparatus AT1 gives an alarm to the operator of the SOD system100A by means of, for example, the ringing of a buzzer sound, thelighting of an alarming lamp, or the display of an alarming signal onthe operating screen.

The wafer W having a coating film formed thereon is transferred by themain transfer mechanism 15 into the low temperature heating unit (LHP)21 so as to be heated to about 100° C. to about 130° C. As a result, thecoating film is dried. Then, the wafer W is further transferred by themain transfer mechanism 15 into the baking unit (DLB) 22 so as toreceive a prescribed baking processing at, for example, about 200° C. toabout 300° C., thereby forming an insulating film on the wafer W. Thebaking process temperature is about 200° C. in the case of using achemical liquid that is available under the trade name of “LKD”, isabout 300° C. in the case of using a chemical liquid that is availableunder the trade name of “SiLK”, is about 240° C. in the case of using achemical liquid that is available under the trade name of “AlCaP”, andis about 200° C. in the case of using a chemical liquid that isavailable under the trade name of “DUO”.

After the baking processing in the baking process unit (DLB) 22, thefirst wafer W transferred out of the carrier C1 is further transferredby the main transfer mechanism 15 into the film thickness measuring unit19 for measuring the thickness of the insulating film formed by thebaking processing. The measured data on the thickness of the insulatingfilm thus formed is transmitted to the tower control apparatus AT1. Ifthe data on the thickness of the insulating film falls within a range ofthe prescribed standard, the tower control apparatus AT1 permits thesecond wafer W et seq. to be processed within the process tower T1. Onthe other hand, where the data on the thickness of the insulating filmfails to fall within the range of the prescribed standard, but fallswithin an allowable range in respect of the correction, the processparameters within the baking unit (DLB) 22 such as the heatingtemperature, the heating time, and the N₂ concentration are corrected.The second wafer W et seq. are processed within the baking unit (DLB) 22in accordance with the corrected process parameters. On the other hand,where the data on the thickness of the insulating film fails to fallwithin the range of the prescribed standard and also fails to fallwithin an allowable range in respect of the correction, a prescribedalarm is given and the processing in the process tower T1 is stopped.

After the baking processing, the wafer W is transferred by the maintransfer mechanism 15 into the delivery unit (TRS) 16 and, then, broughtback into the carrier C1 by the sub-transfer mechanism 12.

Incidentally, depending on the kind of the chemical liquid, formation ofthe insulating film is not finished by the baking processing. To be morespecific, a desired insulating film is obtained in some cases afterapplication of a so-called “curing processing” to the coating film,i.e., a curing processing in which the coating film is heated to atemperature higher than the baking process temperature so as to promotethe crosslinking or the desorption of porogen, thereby curing thecoating film. In this case, a prescribed curing processing is applied tothe wafer W after completion of a prescribed processing that was appliedby the SOD system 100A. The curing processing noted above is applied byusing a curing apparatus that is arranged separately from the SOD system100A.

In the series of processing performed by the SOD system 100A, themeasurement of the film thickness performed by the film thicknessmeasuring unit 19 can be applied to all the wafers W. Alternatively, itis also possible to perform the thickness measurement by using amonitoring wafer formed of, for example, a bare wafer. If the thicknessof the coating film is monitored appropriately, it is possible to detecteasily an abnormality of the film thickness, and it can be found easilyin which process unit of which process tower the abnormality has beencaused. As a result, the wafer W can be supervised easily.

For processing the wafer W in the SOD system 100A, it is possible forthe wafer W to be coated twice with the chemical liquid in order toincrease the thickness of the insulating film. In this case, a firstcoating film is formed on the wafer surface in the coating unit (SCT)18, followed by applying a drying processing to the first coating filmin the low temperature heating unit (LHP) 21 and subsequently applying abaking processing to the dried film in the baking unit (DLB) 22.Further, a surface modifying processing is applied to the baked film inthe UV irradiating unit (DVT) 17, followed by the formation of a secondcoating film, the drying processing, and the baking processing in theorder mentioned. Alternatively, it is also possible to perform theformation of the first coating film, the drying process, the surfacemodifying process, the formation of the second coating film, the dryingprocess and the baking process in the order mentioned. In the case ofemploying the particular method, it is possible to enhance theuniformity of the film thickness, compared with the case of using achemical liquid having a high viscosity. It is also possible to suppressthe solidification of the chemical liquid within the pipe or at the tipof the nozzle.

Other embodiments of the SOD system will now be described. FIG. 15 is ahorizontal cross sectional view schematically showing the constructionof an SOD system 100B prepared by mounting an additional process block 9to the SOD system 100A described previously. The additional processblock 9 is equal in construction to the process block 8. To be morespecific, the additional process block 9 comprises a process tower T2for performing a prescribed processing for forming an insulating film onthe wafer W, a transfer unit (TRS), not shown, for transferring thewafer W into and out of the process block 8, a UV irradiating unit (DVT)17′ arranged on the transfer unit (TRS) referred to above, and a maintransfer mechanism 15′ for transferring the wafer W within theadditional process block 9. A plurality of process units arranged withinthe process tower T2 can be replaced by other process units like theprocess units arranged in the process tower T1. Also, it is possible toreplace the process tower T2 arranged within the additional processblock 9 by another process tower.

FIG. 16 shows the control system of the SOD system 100B. A tower controlapparatus AT2 is equal in construction to the tower control apparatusAT1 described previously and controlling the process tower T2. If thetower control apparatus AT2 is connected to a block control apparatusAB1 for controlling the additional process block 9, the block controlapparatus AB1 automatically recognizes the unit information on each ofthe various process units arranged within the process tower T2. Also,the unit control device for the UV irradiating unit (DVT) 17′ isconnected directly to the block control apparatus AB1. As a result, theblock control apparatus AB1 prepares a process recipe in the additionalprocess block 9. The control device for the main transfer mechanism 15′is also connected directly to the block control apparatus AB1. When theblock control apparatus AB1 is connected to the system control apparatusAS1, the system control apparatus AS1 automatically recognizes theinstallation of the additional process block 9 and prepares the recipefor the transfer and processing of the wafer W in the entire SOD system100B. As described above, the control system in view of the installationof the additional process block 9 can be constructed easily in the SODsystem 100B.

In the SOD system 100B, it is possible for the wafers W housed in, forexample, the first carrier C1 to be processed in the process tower T1and for the wafers W housed in the second carrier C2 to be processed inthe process tower T2. In this case, it is possible for the same kind ofthe insulating films or for the different kinds of insulating films tobe formed in the process tower T1 and the process tower T2. Further, itis possible for a first insulating film to be formed in the processtower T1 and for a second insulating film to be formed on the firstinsulating film in the process tower T2. In this case, it is possiblefor the first insulating film and the second insulating film to be theinsulating films of the same kind or the different kinds. In the case offorming an insulating film of a two-layer structure, the wafer W isprocessed in the UV irradiating unit (DVT) 17•17′ immediately before thewafer W is coated with the chemical liquid for forming the secondinsulating film. Incidentally, where different kinds of insulating filmsare formed in the process tower T1 and the process tower T2, it ispossible to change the construction of the process units arranged ineach of the process towers T1 and T2.

The SOD system 100B makes it possible to install additional facilitieswhile utilizing the SOD system 100A constructed in advance. For example,where it is necessary to reinforce the facilities for increasing theamount of production, it is not advisable to newly install the SODsystem 100A because the new installation is markedly disadvantageous incost and footprint. However, in the case of preparing the SOD system100B by installing the additional process block 9 in the SOD system100A, it is possible to suppress the increase in the footprint and theincrease in the facility cost. In addition, it is possible to increasethe processing capacity of the wafer W.

FIG. 17 is a horizontal cross sectional view schematically showing theconstruction of another SOD system 100C. The SOD system 100C includes aprocess block 8 a in which process towers T1′ and T2′ are arranged in amanner to have the main transfer mechanism 15 sandwiched therebetween.In the SOD system 100C, the wafer W is transferred into and out of eachof the two process towers T1′ and T2′ by using the main transfermechanism 15 alone so as to increase the transfer through-put. The SODsystem 100C is also advantageous in that the footprint is smaller thanthat of the SOD system 100B described previously.

FIG. 18 schematically shows the construction of the process block 8 aincluded in the SOD system 100C. As shown in the drawing, thetemperature control unit (CPL) 20 included in the process block 8 a isnot arranged in any of the process towers T1′ and T2′, but is arrangedintermediate between the delivery unit (TRS) 16 and the UV irradiatingunit (DVT) 17.

The wafer W controlled at a prescribed temperature in the temperaturecontrol unit (CPL) 20 is transferred into the coating unit (SCT) 18arranged in each of the process towers T1′ and T2′. In this fashion, thetemperature control unit (CPL) 20 is used commonly in the process towersT1′ and T2′ in this embodiment. It should be noted in this connectionthat, before the step of coating the wafer W with the chemical liquid inthe coating unit (SCT) 18 for forming an insulating film, the wafer W iscontrolled at a prescribed temperature (e.g., 23° C.) in the temperaturecontrol unit (CPL) 20. The wafer W can be controlled constant at aprescribed temperature in the temperature control unit (CPL) 20regardless of the kind of the chemical liquid used. Such being thesituation, the temperature control unit (CPL) 20 can be commonly usedfor the process towers T1′ and T2′ as pointed out above.

Incidentally, it is possible to form a delivery stage 16 a, which isalso capable of performing the function of the temperature control unit(CPL) 20, in the transfer unit (RRS) 16. In this case, the wafer Whaving the temperature controlled in the delivery stage 16 a istransferred into the process tower T1′ or the process tower T2′. It isalso possible to arrange a plurality of temperature control units (CPL)20 in the delivery unit (TRS) 16.

The processing method of the wafer W in the SOD system 100C issubstantially equal to that in the SOD system 100B described previouslyand, thus, the description thereof is omitted. Prescribed process unitsas required can be arranged appropriately in the space within each ofthe process towers T1′ and T2′. It is also possible to arrange asauxiliary process units the baking process unit (DLB) 22, etc. that arenot used in general.

FIG. 19 is a horizontal cross sectional view schematically showing theconstruction of an SOD system 100D. As shown in the drawing, fourprocess towers T1 to T4 are arranged within a process block 8 b of theSOD system 100D in a manner to surround a main transfer mechanism 15 a.The main transfer mechanism 15 a is substantially equal in constructionto the main transfer mechanism 15 arranged in the SOD system 100A,except that the mechanism 15 a is slidable in the X-direction along arail R. It follows that it is possible for the main transfer mechanism15 a, which is slidable, to transfer the wafer W into and out of each ofthe process units arranged in each of the process towers T1 to T4.

In the SOD system 100D, the process units required for forming aninsulating film of a single layer structure on the wafer W are arrangedin combination within each of the four process towers T1 to T4. Also,tower control apparatuses AT1 to AT4 are connected to the processtowers. T1 to T4, respectively, so as to permit the processing to becontrolled individually for each of the process towers T1 to T4.

It is possible for the same kind of insulating films or different kindsof insulating films to be formed in the process towers T1 to T4. It isalso possible to form successively four insulating films such that afirst insulating film is formed in the process tower T1, followed byforming a second insulating film on the first insulating film in theprocess tower T2 and subsequently forming a third insulating film on thesecond insulating film in the process tower T3 and finally forming afourth insulating film on the third insulating film in the process towerT4. Further, it is possible to transfer a single wafer W into each ofthe process towers T1 and T2 for forming a first insulating film on thewafer W, followed by transferring the wafer W having the firstinsulating film formed thereon into each of the process towers T3 and T4for forming a second insulating film on the first insulating film.

In the SOD system 100D, the main transfer mechanism 15 a is commonlyused for transferring the wafer W into and out of each of the fourprocess towers T1 to T4 so as to make it possible to diminish thefootprint, compared with the case where the main transfer mechanism 15is arranged for each process tower. Also, it is possible for the SODsystem 100D to perform various processing for forming, for example, aninsulating film of a single layer structure, a two-layer structure or afour-layer structure, as described above.

FIG. 20 is a horizontal cross sectional view schematically showing theconstruction of an SOD system 100E, and FIG. 21 is a back viewschematically showing the construction of the SOD system 100E. As shownin the drawings, the SOD system 100E comprises a process block 8 chaving process towers T1″ and T2″ arranged therein. Each of theseprocess towers T1″ and T2″ includes a coating unit (SCT) 18, a filmthickness measuring unit 19, a low temperature heating unit (LHP) 21, abaking unit (DLB) 22, and a curing unit (DLC) 36 for performing a curingprocessing after the baking processing. These process units are stackedone upon the other in the order mentioned so as to form each of theprocess towers T1″ and T2″.

FIG. 22 is a cross sectional view schematically showing the constructionof the curing unit (DLC) 36. As shown in the drawing, the curing unit(DLC) 36 includes a heating chamber 71 and a temperature control processchamber 73 positioned adjacent to the heating chamber 71. Thetemperature control process chamber 73 also acts as a load lock chamber.A gate valve 74, which can be opened or closed, for performing thedelivery of the wafer W is formed between the heating chamber 71 and thetemperature control process chamber 73.

A heating plate 72 is arranged within the heating chamber 71. A heater72 a having an electric power supplied from a power supply section 72 eis buried in the heating plate 72 so as to set the temperature of theheating plate 72 at, for example, 200° C. to 450° C. A proximity pin 72b for supporting the wafer W in a region close to the surface of theheating plate 72 is formed on the surface of the heating plate 72. Also,a lift pin 72 c for moving the wafer W in the vertical direction abovethe heating plate 72 is formed to extend through the heating plate 72.The lift pin 72 c is driven by a lift mechanism 72 d.

A movable temperature control plate 76 holding the wafer W forcontrolling the temperature of the wafer W at, for example, 20° C. to35° C. and a lift pin 76 c are arranged within the temperature controlprocess chamber 73. The temperature control plate 76 can be moved by amoving mechanism 76 b along a guide rail 76 a toward and away from theheating chamber 71. Also, the lift pin 76 c can be moved in the verticaldirection by a lift mechanism 76 d so as to permit the wafer W on themovable temperature control plate 76 to be moved in the verticaldirection. The wafer W is transferred between the main transfermechanism 15 and the curing unit (DLC) 36 through a wafer transfer port73 a (see FIG. 20) on the side of the temperature control processchamber 73. The wafer transfer port 73 a is opened and closed by ashutter 73 b (see FIG. 20).

A nitrogen gas (N₂) is supplied from a nitrogen gas supply mechanism 75into each of the heating chamber 71 and the temperature control processchamber 73. On the other hand, it is possible to exhaust the heatingchamber 71 and the temperature control process chamber 73 by using anexhaust apparatus such as a vacuum pump (not shown).

In the curing unit (DLC) 36, it is possible to lower the oxygenconcentration and to lower the pressure within the heating chamber 71 bysupplying a N₂ gas from the nitrogen gas supply mechanism 75 into theheating chamber 71 while exhausting the atmosphere in the heatingchamber 71. The wafer W transferred by the main transfer mechanism 15into the temperature control process chamber 73 through the wafertransfer port 73 a of the temperature control process chamber 73 isreceived by the lift pin 76 c and, then, the wafer W is disposed on themovable temperature control plate 76. Then, a N₂ gas is supplied fromthe nitrogen gas supply mechanism 75 into the temperature controlprocess chamber 73 while discharging the atmosphere from within thetemperature control process chamber 73 so as to lower the oxygenconcentration and to lower the pressure within the temperature controlprocess chamber 73. Further, the gate valve 74 is opened so as to movethe temperature control plate 76 into the heating chamber 71, and thewafer W is delivered from the temperature control plate 76 onto the liftpin 72 c. When the temperature control plate 76 is brought back into thetemperature control process chamber 73, the gate valve 74 is closed. Onthe other hand, the wafer W is disposed on the heating plate 72 bymoving downward the lift pin 72 c. Further, the atmosphere within theheating chamber 71 is adjusted again to have a prescribed reducedpressure having a prescribed low oxygen concentration, and the waferdisposed on the heating plate 72 is heated to a prescribed temperatureso as to apply a prescribed curing processing to the wafer W. The waferW after completion of the curing processing is delivered onto themovable temperature control plate 76 moved into the heating chamber 71and, then, brought back into the temperature control process chamber 73so as to have the wafer W controlled at a prescribed temperature.Further, the pressure inside the temperature control process chamber 73is brought back to the normal pressure. Under this condition, the wafertransfer port 73 a is opened so as to have the wafer W after the curingprocessing transferred out of the temperature control process chamber 73by the main transfer mechanism 15.

A unit control device 90G permits controlling the various operationsperformed within the curing unit (DLC) 36 including, for example, thecontrol of the power output from the power supply section 72 e into theheater 72 a (i.e., the temperature control of the heating plate 72), thevertical movement of each of the lift pins 72 c and 76 c, theopening-closing operation of the gate valve 74, the movement of themovable temperature control plate 76, and the degree of vacuum and theN₂ concentration within each of the heating chamber 71 and thetemperature control process chamber 73. In the case of, for example, theprocess tower T1″, the unit information on the curing unit (DLC) 36 istransmitted to the tower control apparatus AT1, if the unit controldevice 90G is connected to the tower control apparatus AT1. As a result,the tower control apparatus AT1 prepares a process recipe including thecuring processing. Also, the tower control apparatus AT1 is capable ofchanging the control parameter of the curing unit (DLC) 36 into anappropriate value based on the result of the measurement of the filmthickness performed in the film thickness measuring unit 19.

The SOD system 100E makes it possible to diminish in total the arearequired for installing the entire apparatus, compared with the casewhere the curing processing is carried out outside the SOD system, i.e.,where the apparatus for the curing processing is installed separatelyfrom the SOD system. Also, since the transfer distance of the wafer Wbetween the baking unit (DLB) 22 and the curing unit (DLC) 36 isshortened, it is possible to increase the transfer through-put.

Where, for example, two insulating films are formed successively on thewafer W by using the SOD system 100E, it is possible to have theprocessing for forming the first insulating film in the process towerT1′ finished by the baking processing and to have the processing forforming the second insulating film in the process tower T2″ finished bythe curing processing. In this case, the first insulating film and thesecond insulating film are subjected to the curing processingsimultaneously during the curing processing performed in the processtower T2″. Such being the situation, it is not absolutely necessary toarrange the curing unit (DLC) 36 in the process tower T1″.

FIG. 23 is a horizontal cross sectional view schematically showing theconstruction of an SOD system 100F, and FIG. 24 is a back viewschematically showing the construction of the SOD system 100F. As shownin the drawings, the SOD system 100F comprises a process block 8 dprepared by modifying the process block 8 a included in the SOD system100C described previously. To be more specific, a curing process towerTC prepared by stacking a plurality of curing units (DLC) 36 one uponthe other so as to form a multi-stage structure is arranged in theprocess block 8 d in place of the process tower T2. The wafer W aftercompletion of the baking processing performed in the process tower T1 issuccessively transferred by the main transfer mechanism 15 into any ofthe curing units (DLC) 36 arranged within the curing process tower TC soas to have a prescribed curing processing applied to the wafer W.

The curing process tower TC is controlled by a tower control apparatusAc. When the tower control apparatus Ac is connected to the systemcontrol apparatus AS1, the system control apparatus AS1 recognizes theconstruction of the curing process tower TC and prepares a processingrecipe of the wafer W in the SOD system 100F. The system controlapparatus AS1 is capable of changing the control parameter of the curingunit (DLC) 36 into an appropriate value based on the result of thethickness measurement performed by the film thickness measuring unit 19.

The SOD system 100F comprises the curing unit (DLC) 36 like the SODsystem 100E. Therefore, compared with the case where the curing processunit is installed separately from the SOD system, the transfer distanceof the wafer W between the baking unit (DLB) 22 and the curing unit(DLC) 36 is short so as to increase the wafer transfer through-put.Also, since the plural curing units (DLC) 36 each requiring a highprocess temperature and a long process time are arranged separately fromthe other process units, it is possible to suppress the detrimentaleffect given from the curing units (DLC) 36 to the other process units.

Incidentally, it is possible to arrange, for example, a batch type heatprocessing furnace for subjecting, for example, 25 to 50 wafers to thecuring processing simultaneously in place of the curing process towerTC.

For performing the curing processing required for forming an insulatingfilm, it is possible to use an apparatus for performing the curingprocessing by using an electron beam, i.e., a so-called “EB curingunit”, in place of the method described above in which the wafer W issubjected to a thermal process.

FIGS. 25 and 26 are a horizontal cross sectional view and a verticalcross sectional view, respectively, each schematically showing theconstruction of an EB curing unit (EBC) 37. As shown in the drawings,the EB curing unit (EBC) 37 comprises a casing 80. The casing 80 ispartitioned by a gate valve 83 into an electron beam process chamber 81and a wafer transfer chamber 82 that also acts as a load lock chamber. AN₂ gas is supplied from a nitrogen gas supply mechanism (not shown) intoeach of the electron beam process chamber 81 and the wafer transferchamber 82. On the other hand, the atmosphere within the electron beamprocess chamber 81 and the wafer transfer chamber 82 can be exhausted byan exhaust apparatus (e.g., a vacuum pump).

An internal transfer arm 84 having a multi-joint structure is arrangedwithin the wafer transfer chamber 82, though the joint portion is notshown in detail in the drawing. The wafer transfer chamber 82 can beroughly divided into a wafer delivery zone P1 and an arm retreating zoneP2. The internal transfer arm 84 is movable between the wafer deliveryzone P1 and the arm retreating zone P2 and between the arm retreatingzone P2 and the electron beam process chamber 81. A lift pin 85 a thatcan be moved by a lift mechanism 85 b in the vertical direction ismounted within the wafer delivery zone P1. Also, a wafer transfer port86 a that can be opened and closed by a shutter 86 b is formed in thewafer transfer chamber 82 on the side of the wafer delivery zone P1.

Arranged within the electron beam process chamber 81 are a stage 87 formounting the wafer W thereon, an electron beam generating device 88 forirradiating the wafer W disposed on the stage 87 with an electron beam,and a lift pin 89 a that can be moved in the vertical direction by alift mechanism 89 b. FIG. 27 is a plan view showing the construction ofthe electron beam irradiating device 88. As shown in the drawing, aplurality of electron beam irradiating tubes 88 a are arranged in a highdensity within a circular region having a prescribed diameter so as toform the electron beam irradiating device 88. Incidentally, it ispossible to arrange on the stage 87 a temperature control device forcontrolling the wafer W at a desired temperature.

In the EB curing unit (EBC) 37 of the construction described above, a N₂gas atmosphere of the normal pressure is set up first within the wafertransfer chamber 82 and, then, the shutter 86 b is driven so as to openthe wafer transfer port 86 a under the state that the internal transferarm 84 is retreated into the arm retreating zone P2. Then, the arm 61holding the wafer W after completion of the baking processing is movedinto the wafer delivery zone P1 through the wafer transfer port 86 a,followed by moving upward the lift pin 85 a. As a result, the wafer W isheld by the lift pin 85 a. After the arm 61 has been retreated, thewafer transfer port 86 a is closed so as to set up an atmosphere of areduced pressure having a prescribed oxygen concentration within each ofthe wafer transfer chamber 82 and the electron beam process chamber 81.Then, the internal transfer arm 84 is moved into the wafer delivery zoneP1, and the lift pin 85 a is moved downward so as to permit the wafer Wto be held by the internal transfer arm 84. Further, the gate valve 83is opened and the internal transfer arm 84 is moved into the electronbeam process chamber 81, followed by moving upward the lift pin 89 a. Asa result, the wafer W is delivered from the internal transfer arm 84onto the lift pin 89 a. In the next step, the internal transfer arm 84is brought back into the wafer transfer chamber 82, and the lift pin 89a is moved downward so as to permit the wafer W to be disposed on thestage 87. After a prescribed vacuum atmosphere is set up within theelectron beam process chamber 81, the electron beam generating device 88is operated so as to irradiate the wafer W with an electron beam,thereby carrying out a curing processing. Incidentally, it is desirableto introduce a process gas such as an argon gas and a methane gas intothe electron beam process chamber 81 during the curing processing inorder to cool the electron beam irradiating tube 88 a and to promote theprocess reaction.

After the curing processing, the process gas is exhausted from theelectron beam process chamber 81, and a N₂ gas is supplied into theelectron beam process chamber 81 so as to cause the wafer transferchamber 82 and the electron beam process chamber 81 to be equal to eachother in the internal atmosphere. Under this condition, the gate valve83 is opened, and the internal transfer arm 84 is allowed to hold thewafer W by the procedures opposite to those for allowing the wafer W tohave been disposed on the stage 87 previously. Then, the internaltransfer arm 84 is moved into the wafer delivery zone P1 within thewafer transfer chamber 82 so as to deliver the wafer W onto the lift pin85 a. After delivery of the wafer W, the internal transfer arm 84 isretreated into the arm retreating zone P2, and the wafer transfer port86 a is opened so as to move the arm 61 not holding the wafer W into thewafer delivery zone P1. Then, the wafer W is delivered onto the arm 61.Where the wafer W that is to be subjected to the curing processing inthe next step is held by another arm 61, the wafer W is transferred intothe wafer delivery zone P1 and, then, the wafer W is transferred withinthe EB curing unit (EBC) 37 so as to receive the curing processing.

It is possible to install the EB curing unit (EBC) 37 (or curing unit(DLC) 36) within any of the SOD systems 100A to 100D describedpreviously as an additional facility. It is also possible to replace thecuring unit (DLC) 36 included in any of the SOD systems 100E and 100F bythe EB curing unit (EBC) 37.

FIG. 28 is a horizontal cross sectional view schematically showing theconstruction of an SOD system 100B′, which is prepared by adding the EBcuring unit (EBC) 37 to the SOD system 100B described previously. In theSOD system 100B′, an electric unit 70 is arranged adjacent to the EBcuring unit (EBC) 37. Various control devices for controlling the EBcuring unit (EBC) 37 such as the control device for controlling thepower source of the electron beam generating device 88, the controldevice for controlling the temperature of the stage 87 and the controldevice for controlling the internal transfer arm 84 are mounted withinthe electric unit 70.

When the electric unit 70 positioned adjacent to the EB curing unit(EBC) 37 is connected to the system control apparatus AS1, the systemcontrol apparatus AS1 grasps the unit construction, etc. of the entireSOD system 100B′ so as to prepare the process recipe and the transferrecipe of the wafer W within the entire SOD system 100B′. In the SODsystem 100B′, the main transfer mechanism 15 performs the delivery ofthe wafer W after completion of the baking processing within the processtowers T1 and T2 onto the wafer delivery zone P1 of the EB curing unit(EBC) 37.

In the SOD system 100B′, the EB curing unit (EBC) 37 is arranged outsidethe system, with the result that the maintenance can be performed easilywhen the EB curing unit (EBC) 37 have got out of order.

Incidentally, it is possible for the EB curing unit (EBC) 37 to be of amulti-stage stacked structure. The arranging position of the EB curingunit (EBC) 37 is not limited to the position shown in FIG. 28. It isalso possible to arrange the EB curing unit (EBC) 37 in the positionwhere the main transfer mechanism 15′ is capable of delivering the waferW to the wafer delivery zone P1 within the EB curing unit (EBC) 37. Forexample, it is possible to arrange the EB curing unit (EBC) 37 on theleft side of the additional process block 9 shown in FIG. 28. Further,it is possible to arrange two EB curing units (EBC) 37, one in theposition shown in FIG. 28 and the other in the position on the left sideof the additional process block 9.

FIG. 29 is a horizontal cross sectional view schematically showing theconstruction of an SOD system 100F′. The SOD system 100F′ comprises aprocess block 8 e prepared by modifying the process block 8 d includedin the SOD system 100F. To be more specific, an EB curing process towerTC′ prepared by stacking two EB curing units (EBC) 37 one upon the otheris arranged in the process block 8 e included in the SOD system 100F′ inplace of the curing process tower TC arranged in the process block 8 dincluded in the SOD system 100F. The EB curing process tower TC′ is alsodetachable from the process block 8 e like the process tower T1.Therefore, even where the EB curing unit (EBC) 37 has got out of order,the EB curing unit (EBC) 37 can be repaired easily by pulling the EBcuring unit (EBC) 37 out from the process block 8 e.

Where the EB curing unit (EBC) 37 is arranged within, for example, theprocess block 8 of the SOD system 100A, it is possible to arrange the EBcuring unit (EBC) 37 on the upper side of the UV irradiating unit (DVT),as in an SOD system 100A′ shown in FIG. 30. The UV irradiating unit(DVT) is not shown in FIG. 30. It is desirable for the EB curing unit(EBC) 37 to be detachable singly from a process block 8 f in this case,too, so as to facilitate the maintenance of the EB curing unit (EBC) 37.

Where the EB curing unit (EBC) 37 is arranged in an SOD system as in theSOD systems 100A′, 100B′, and 100F′, it is desirable to arrange thevacuum section (i.e., the casing 80) of the EB curing unit (EBC) 37 andthe electric unit 70 a prescribed distance apart from each other inorder to facilitate the maintenance of mainly the vacuum section (i.e.,the electron beam process chamber 81 and the wafer transfer chamber 82)of the EB curing unit (EBC) 37.

The present invention is not limited to the embodiments described above.For example, it is possible to arrange a plurality of baking units (DLB)22 within the process tower T1 of the SOD system 100A without arrangingthe low temperature heating unit (LHP) 21 within the process tower T1.In this case, the drying processing and the baking processing of thecoating film are consecutively carried out in the plural baking units(DLB) 22.

Also, where the additional process block 9 that is similar inconstruction to the process block 8 is installed within the SOD system100A together with the process block 8, the number of additional processblocks is not limited to one. As described previously, the SOD system100B was prepared by installing the additional process block 9 similarin construction to the process block 8 within the SOD system 100Atogether with the process block 8. Likewise, the SOD system 100B′ wasprepared by further installing the EB curing unit (EBC) 37 within theSOD system 100B. In this fashion, it is possible to construct anothereffective SOD system 100C′ by installing an additional process block 9a, which is similar in construction to the process block 8 a installedwithin the SOD system 100C, and the EB curing unit (EBC) 37 within theSOD system 100C. FIG. 31 is a horizontal cross sectional viewschematically showing the construction of the SOD system 100C′ referredto above. Since the four process towers T1 to T4 are installed withinthe SOD system 100C′, it is possible to process the wafer W based on therecipe similar to that for, for example, the SOD system 100D. Inaddition, the curing processing can be performed within the EB curingunit (EBC) 37.

Likewise, an SOD system 100D′ can be prepared by installing anadditional process block 9 b, which is similar in construction to theprocess block 8 b installed within the SOD system 100D, within the SODsystem 100D together with the process block 8 b. FIG. 32 is a horizontalcross sectional view schematically showing the construction of the SODsystem 100D′ referred to above. In the SOD system 100D′, it is possibleto form the same kind or different kinds of insulating films on a singlewafer W by operating the eight process towers T1 to T8. It is alsopossible to transfer a single wafer W into each of the process towers T1to T8 so as to form an insulating film of a single layer structure oneach of the eight wafers W. Further, it is possible to form a firstinsulating film on the wafer W in the process block 8 b, followed byforming a second insulating film on the first insulating film in theadditional process block 9 b.

As apparent from the comparison among the SOD systems 100A, 100C and100D, an optional number of process towers can be installed within theprocess block. Also, it is possible to construct a new SOD systemequipped with six process towers by installing the additional processblock 9 b, which is similar in construction to the process block 8 bincluded in the SOD system 100D, in the position adjacent to the processblock 8 a included in the SOD system 100C.

In the various SOD systems described above, it is possible to arrange aninspecting tower, which is prepared by stacking a plurality of filmthickness measuring units 19, in place of the process tower. Also, it ispossible for the tower control apparatus AT1 to be constructed toperform solely the function of generating an alarm in response to aprescribed abnormality without performing the function of correcting thecontrol parameter of each of the process units constituting the processtower T1.

Further, depending on the SOD material used, it is necessary to carryout additional processing after the coating step such as the processingunder an ammonia gas atmosphere and the chemical processing like thesolvent exchange processing. Therefore, it is possible to mount an agingunit, a solvent exchange unit, etc. in the process tower.

In the embodiments described above, the coating unit (SCT) 18 arrangedwithin the process tower is constructed such that the pump 26 isarranged in the coater area 18A. However, the coating unit (SCT) is notlimited to the particular construction. For example, FIG. 33schematically shows the construction of another coating unit (SCT) 18′.In this case, the pump 26 is arranged within a tank area 18B′ in amanner to be positioned sideward of the chemical liquid tank 29. Also,FIG. 34 schematically shows the construction of still another coatingunit (SCT) 18″. In this case, a tank area 18B″ of the coating unit (SCT)18″ is divided into an upper stage and a lower stage. The chemicalliquid tank 29 is arranged in the lower stage of the tank area 18B″, andthe pump 26 is arranged in the upper stage of the tank area 18B″. Thelength of the liquid supply pipe arranged between the pump 26 and thesupply nozzle 25 can be shortened in each of these coating units (SCT)18′ and 18″, too.

The embodiments described above are directed to an apparatus forprocessing the wafer W. However, it is also possible to apply thetechnical idea of the present invention to an apparatus for processing aglass substrate used in, for example, a liquid crystal display. Also,the technical idea of the present invention can be applied to not onlythe formation of an insulating film by the SOD method but also to theformation of an SOG (Spin on Glass) film. The surface of the film formedby the CVD method is irregular. Therefore, a SiO₂ film is formed on thesurface of the film formed by the CVD method so as to obtain a flatsurface. The SOG film noted above denotes the SiO₂ noted above. The SOGfilm can be formed by forming a coating film of a chemical liquid on thewafer surface by the spin coating method, followed by applying a heatprocessing to the wafer, like the SOD method.

INDUSTRIAL APPLICABILITY

As described above, the present invention is adapted for application tothe SOD system for forming an insulating film on various substrates suchas a semiconductor wafer, though the application of the presentinvention is not limited to the particular SOD system. The presentinvention can also be applied widely to the apparatus for coating asubstrate with a chemical liquid for forming a coating film, followed byapplying a heat processing to the coating film. For example, the presentinvention can also be applied to the apparatus for forming a resistfilm.

1. An insulating film-forming apparatus, comprising: a substrate processsection for applying a prescribed processing to a substrate for formingan insulating film on the substrate; a substrate transfer section fortransferring the substrate from the outside into the substrate processsection; and a substrate transfer mechanism for transferring thesubstrate between the substrate process section and the substratetransfer section; wherein: the substrate process section includes aprocess tower housed in a housing and consisting of a plurality ofprocess units, which are stacked one upon the other, for performing aseries of processing for forming an insulating film on the substrate,said process tower including a coating unit for coating the substratewith a chemical liquid containing a material of the insulating film soas to form a coating film, and a heating unit for heating the substratehaving the coating film formed thereon; and the process tower isdetachable from the substrate process section.
 2. The insulatingfilm-forming apparatus according to claim 1, wherein the process towercomprises a frame of a prescribed shape, the plural process units areindividually detachable from the housing of the process tower.
 3. Theinsulating film-forming apparatus according to claim 1, wherein: each ofthe plural process units is equipped with a unit control device forcontrolling the processing of the substrate within the process unit; theprocess tower is equipped a tower control apparatus that can beconnected to the unit control devices so as to control a series ofprocessing applied to the substrate by the plural process units arrangedwithin the process tower; and the tower control apparatus automaticallyrecognizes the process unit when the unit control device is connected tothe tower control apparatus.
 4. The insulating film-forming apparatusaccording to claim 3, further comprising a film thickness measuringsection for measuring the thickness of the insulating film, wherein: thetower control apparatus is constructed to control the process parameterof each of the plural process units arranged within the process tower;and the tower control apparatus controls the process parameter of thecoating unit based on the thickness, which is measured by the filmthickness measuring section, of the coating film formed in the coatingunit.
 5. The insulating film-forming apparatus according to claim 3,further comprising a film thickness measuring section for measuring thethickness of the insulating film, wherein: the tower control apparatusis constructed to control the process parameter of each of the pluralprocess units arranged within the process tower; and the tower controlapparatus controls the process parameter of the heating unit based onthe thickness, which is measured by the film thickness measuringsection, of the insulating film processed in the heating unit.
 6. Theinsulating film-forming apparatus according to claim 1, wherein: thesubstrate transfer section includes a table on which is disposed acarrier housing a plurality of substrates; the substrate process sectionincludes a transfer unit on which the substrate is temporarily disposed;and the substrate transfer mechanism includes: a first transfer devicearranged in the substrate transfer section for transferring thesubstrate between the table and the transfer unit; and a second transferdevice arranged in the substrate process section for transferring thesubstrate between the transfer unit and the plural process units.
 7. Theinsulating film-forming apparatus according to claim 1, wherein theprocess tower includes a temperature control unit for controlling thesubstrate before coating with the chemical liquid at a prescribedtemperature.
 8. The insulating film-forming apparatus according to claim1, wherein the substrate process section includes a plurality of processtowers.
 9. The insulating film-forming apparatus according to claim 8,wherein each of the plural process towers includes a plurality ofprocess units for forming an insulating film, the plural process towersform the same kind of the insulating film.
 10. The insulatingfilm-forming apparatus according to claim 8, wherein at least one of theplural process towers includes a plurality of process units for formingan insulating film differing in kind from the insulating film formed inanother process tower.
 11. The insulating film-forming apparatusaccording to claim 8, wherein a first insulating film is formed on thesubstrate in one of the plural process towers, and a second insulatingfilm is formed on the first insulating film in another process tower.12. The insulating film-forming apparatus according to claim 1,comprising a plurality of substrate process sections, wherein at leastone substrate process section is detachable from the other substrateprocess sections.
 13. The insulating film-forming apparatus according toclaim 1, wherein the substrate process section further includes a curingunit for applying a curing processing to the insulating film after theheat processing applied by the heat processing unit.
 14. The insulatingfilm-forming apparatus according to claim 13, wherein the curing unitincludes an electron beam irradiating mechanism for curing theinsulating film by the electron beam irradiating processing.
 15. Theinsulating film-forming apparatus according to claim 13, wherein thecuring unit is arranged to constitute the uppermost section of theprocess tower.
 16. The insulating film-forming apparatus according toclaim 13, comprising a plurality of curing units that are stacked oneupon the other so as to form a tower.
 17. The insulating film-formingapparatus according to claim 6, further comprising a curing unitarranged in a position adjacent to the substrate process section so asto permit the substrate to be transferred into and out of the curingunit by the second substrate transfer device, said curing unit servingto apply a curing processing to the insulating film after the heatprocessing applied by the heating unit.
 18. The insulating film-formingapparatus according to claim 17, comprising a plurality of curing units,which are arranged in a position adjacent to the substrate processsection and stacked one upon the other so as to form a tower.
 19. Theinsulating film-forming apparatus according to claim 18, wherein thecuring unit includes an electron beam irradiating mechanism for curingthe insulating film by the electron beam irradiating processing.
 20. Theinsulating film-forming apparatus according to claim 1, wherein thecoating unit comprises: a coating process section having a substrateholding mechanism for holding the substrate substantially horizontal, achemical liquid supply nozzle for supplying a chemical liquid onto thesubstrate held by the substrate holding mechanism, and a cup surroundingthe side surface of the substrate held by the substrate holdingmechanism and equipped with a exhaust port of the chemical liquid formedat the bottom; and a waste liquid recovery section arranged below thecoating process section and having a waste liquid tank for storing thewaste liquid exhausted from the exhaust port and with a waste liquidpassageway for introducing the waste liquid exhausted from the exhaustport into the waste liquid tank.
 21. The insulating film-formingapparatus according to claim 20, wherein: the waste liquid recoverysection further comprises a chemical liquid tank storing the chemicalliquid used in the coating process section; and the coating processsection further comprises a pump for supplying the chemical liquid fromthe chemical liquid tank into the chemical liquid supply nozzle.
 22. Theinsulating film-forming apparatus according to claim 20, wherein thewaste liquid recovery section further comprises a chemical liquid tankstoring the chemical liquid used in the coating process section, and apump arranged sideward of the chemical liquid tank for supplying thechemical liquid from the chemical liquid tank into the chemical liquidsupply nozzle.
 23. The insulating film-forming apparatus according toclaim 20, wherein the waste liquid recovery section further comprises achemical liquid tank storing the chemical liquid used in the coatingprocess section, and a pump arranged on the upper side of the chemicalliquid tank for supplying the chemical liquid from the chemical liquidtank into the chemical liquid supply nozzle.
 24. The insulatingfilm-forming apparatus according to claim 1, wherein: each of the pluralprocess units is housed in a casing, and the process tower includes ahousing which accommodates the plural casings accommodating the processunits; and at least the casing accommodating the heating unit and thecasing accommodating the coating unit are arranged within the housingsuch that an air passageway is formed therebetween so as to achieve theheat insulation.
 25. The insulating film-forming apparatus according toclaim 24, further comprising an air blowing mechanism for blowing theair having the controlled temperature and humidity into the coating unitso as to control the temperature and humidity of the coating unit,wherein the casing accommodating the coating unit is constructed topermit the air blown from the air blowing mechanism into the coatingunit to be exhausted from the coating unit into the air passageway.